A conventional computer keyboard has no self-illuminating function. Generally, a dim environment becomes hindrance from operating the keyboard. Recently, an illuminated keyboard has been developed. When the illuminated keyboard is used in the dim environment, the user can accurately depress desired keys by means of the light scattered from peripheries of the keys or middle portions of the keys. In addition, the light produced by the illuminated keyboard results in an aesthetically pleasing appearance. For example, Chinese Patent Application No. CN200820125924.4 disclosed an illuminated keyboard. The illuminated keyboard sequentially comprises a character keycap, a connecting member, a light-transmissible base plate, a light-guiding plate, a light emitting diode, and a reflector. The character keycap and the light-transmissible base plate are connected with each other through the connecting member. As such, the character keycap is movable with respect to the light-transmissible base plate in the vertical direction. The light emitting diode is disposed on the reflector, and accommodated within a receptacle of the light-guiding plate. Through the reflector and the light-guiding plate, the light emitted by the light emitting diode is guided to the region under the character keycap so as the illuminate the whole illuminated keyboard.
Since the conventional illuminated keyboard needs an additional light-guiding plate and associated keyboard component to guide light, the cost of guiding light is high. Moreover, when the conventional illuminated keyboard is used in a dim environment, a serious light leakage problem occurs and the illuminated keyboard becomes less identifiable.